A load cell may be a device (e.g., a transducer) that converts a force to a differential signal (e.g., a differential electric signal). The load cell may be used for a variety of industrial applications (e.g., a scale, a truck weigh station, a tension measuring system, a force measurement system, a load measurement system, etc.) The load cell may be created using a strain gauge. The strain gauge can be used to measure deformation (e.g., strain) of an object. The strain gauge may include a flexible backing which supports a metallic foil pattern etched onto the flexible backing. As the object is deformed, the metallic foil pattern is deformed, causing its electrical resistance to change.
The strain gauge can be connected with other strain gauges to form a load cell in a Wheatstone-bridge configuration (e.g., constructed from four strain gauges, one of which has an unknown value, one of which is variable, and two of which are fixed and equal, connected as the sides of a square). When an input voltage is applied to the load cell in the Wheatstone-bridge configuration, an output may become a voltage proportional to the force on the load cell. The output may require amplification (e.g., 125×) by an amplifier before it can be read by a user (e.g., because the raw output of the Wheatstone-bridge configuration may only be a few milli-volts). In addition, the load cell in the Wheatstone-bridge configuration may consume a significant amount of power when in operation (e.g., in milli-watts of power).
Manufacturing the load cell in the Wheatstone-bridge configuration may involve a series of operations (e.g., precision machining, attaching strain gauges, match strain gauges, environmental protection techniques, and/or temperature compensation in signal conditioning circuitry, etc.). These operations may add complexity that may deliver a yield rate of only 60% and may allow a particular design of the load cell to only operate for a limited range (e.g., between 10-5,000 lbs.) of measurement. In addition, constraints of the Wheatstone-bridge configuration may permit only a limited number of form factors (e.g., an s-type form factor and/or a single point form factor, etc.) to achieve desired properties of the load cell. The complexity of various operations to manufacture the load cell may drive the costs up (e.g., hundreds and thousands of dollars) for many industrial applications.